Tektronix TDSUSB2, Руководство пользователя

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Operating Basics
Figure 23: Configuring Packet Parameter measurement for device
5. Select the Device option to display the different tests for the DUT. The
available tests are:
EL_21, EL_22, EL_25: You can perform three separate measurements
on an acquired waveform
EL_22: You can perform a single measurement on an acquired
waveform
6. Use the drop down arrow in the Differential field to set the channel source.
The available options are: Ch1-Ch4, Ref1-Ref4.
7. Select the Run button.
8. To generate reports, select Utilities> Report Generator.
Packet Parameter Measurement
Packet parameter measurement is for high-speed Host controller and Device.
There are several important packet characteristics for upstream and downstream
signaling. The measurement calculates the SYNC field length, EOP length and
inter packet gap. The acceptable range of EOP for all transmitted packets (except
SOFs) must be between 7.5 and 8.5 bits. The packet parameter algorithm
calculates the EOP depending on this range.
The acceptable range of inter packet gap is between 88 bits to 192 bits. The
SYNC field for all transmitted packets is calculated by counting the bits to check
for 32-bit SYNC field. The inter packet delay and SYNC status is calculated
between the EOP indexes. The EOP width in time is calculated by dividing the
EOP width by 480 Mbps.
44 TDSUSB2 Universal Serial Bus Measurement Package